Suppose i place an order and the order is pending.If the internet is disconnected will the order be filled?
Yes, it will be filled! Once you place the order, your order will be filled when the price hit that order price. It has nothing to do with your internet connection, because you already placed the order before getting disconnected!
Once you place the order it goes directly in the exchanges’s order books and it will be filled accordingly. Your net connectivity has nothing to do with your order being filled or not. Now you do need your connection to monitor your position or even know whether the order got filled or not